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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 | // SPDX-License-Identifier: GPL-2.0-or-later /* Kernel module to match IPComp parameters for IPv4 and IPv6 * * Copyright (C) 2013 WindRiver * * Author: * Fan Du <fan.du@windriver.com> * * Based on: * net/netfilter/xt_esp.c */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/in.h> #include <linux/module.h> #include <linux/skbuff.h> #include <linux/ip.h> #include <linux/netfilter/xt_ipcomp.h> #include <linux/netfilter/x_tables.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Fan Du <fan.du@windriver.com>"); MODULE_DESCRIPTION("Xtables: IPv4/6 IPsec-IPComp SPI match"); MODULE_ALIAS("ipt_ipcomp"); MODULE_ALIAS("ip6t_ipcomp"); /* Returns 1 if the spi is matched by the range, 0 otherwise */ static inline bool spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert) { bool r; pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n", invert ? '!' : ' ', min, spi, max); r = (spi >= min && spi <= max) ^ invert; pr_debug(" result %s\n", r ? "PASS" : "FAILED"); return r; } static bool comp_mt(const struct sk_buff *skb, struct xt_action_param *par) { struct ip_comp_hdr _comphdr; const struct ip_comp_hdr *chdr; const struct xt_ipcomp *compinfo = par->matchinfo; /* Must not be a fragment. */ if (par->fragoff != 0) return false; chdr = skb_header_pointer(skb, par->thoff, sizeof(_comphdr), &_comphdr); if (chdr == NULL) { /* We've been asked to examine this packet, and we * can't. Hence, no choice but to drop. */ pr_debug("Dropping evil IPComp tinygram.\n"); par->hotdrop = true; return false; } return spi_match(compinfo->spis[0], compinfo->spis[1], ntohs(chdr->cpi), !!(compinfo->invflags & XT_IPCOMP_INV_SPI)); } static int comp_mt_check(const struct xt_mtchk_param *par) { const struct xt_ipcomp *compinfo = par->matchinfo; /* Must specify no unknown invflags */ if (compinfo->invflags & ~XT_IPCOMP_INV_MASK) { pr_info_ratelimited("unknown flags %X\n", compinfo->invflags); return -EINVAL; } return 0; } static struct xt_match comp_mt_reg[] __read_mostly = { { .name = "ipcomp", .family = NFPROTO_IPV4, .match = comp_mt, .matchsize = sizeof(struct xt_ipcomp), .proto = IPPROTO_COMP, .checkentry = comp_mt_check, .me = THIS_MODULE, }, { .name = "ipcomp", .family = NFPROTO_IPV6, .match = comp_mt, .matchsize = sizeof(struct xt_ipcomp), .proto = IPPROTO_COMP, .checkentry = comp_mt_check, .me = THIS_MODULE, }, }; static int __init comp_mt_init(void) { return xt_register_matches(comp_mt_reg, ARRAY_SIZE(comp_mt_reg)); } static void __exit comp_mt_exit(void) { xt_unregister_matches(comp_mt_reg, ARRAY_SIZE(comp_mt_reg)); } module_init(comp_mt_init); module_exit(comp_mt_exit); |